Electromechanical switching system



|.A n. Bunn. Ci 41 crm|\1BURG, AND F..s. HURD. ELECTROMECHANICAL SWITCHING SYSTEM.y

Patented Apr. 4, 1922.

8 SHEETS-SHEET 1.

APPLICATION FILED MAY 25 |914.

my, C. W v

I. D. BUDD. C. I. CRONBURG, AND F. S. HUHD.

ELECTROMECHANICAL SWITCHING SYSTEM. APPLICATION FILED MAY 25, 19H4.V

1,411,478., Patented Apr. 4, 1922B 8 SHLL [S-SHEET 2.

L'D. BUDD. C. I. CRONBURG. AND F.,S. HURD.

ELEGTROMECHANICAL SWITCHING SYSTEM.

APPLICATION FILED MAY 25,1914.

1,41 1,478, Patented Apr. 4, 1922.

8 SHI-.ETS`SHEET 3.

l. D. BUDD,'C. CRONBURG, AND F. S. HURD. ELECTROMECHANICAL SWITCHING SYSTEM.

APPLICATION FILED MAY 25, 1914. I

Patented Apr. 4, 1922.

8 snails-SHEET 4.

I. D. BUDD. C. I. CRONBIIRG, AND"F. SIHURD.

ELECTRDMECHANICAL SWITCHING SYSTEM.

APPLICATION FILED MAY 25, I9I4.

Zfzeaf/ KM Mw; 55%

l. D. BUDD. C. l. CRONBURG, AND F. S. HURD. ELECTROMECHANICAL swlTcHlNG SYSTEM.

APPLICATION FILED MAY 25, 1914.

Patented Apr. 4,1922,

8 SHN: fS-SHEET 6.

I. D. BUDD APPLICATION FILED MAY 2,5. 1914. 1,41 1,478.

Patented Apr. 4, 1922.

8 SHttIS-SHEET 7.

Izzfzf Zac udc man fl |.`D. BUDD, C. I. CRONBURG, AND F. S. HURD.

ELEcTRoMEcHANlcAL swlTcHlNG SYSTEM.

APPLICATION FILE'D MAY 25, 1914.

1,41 1,478 Patented Apr. 4, 1922.

8 SHEES-SHEET 8.

L36/ min/557 :lv A

UNITED STATES ISAAC D. BUDD AND CLAUDE I, CRONBURG, OF CHICAGO, ANDKFREEMAN S. HURD, OF I PATENT OFFICE.

OAK PARK, ILLINOIS, ASSIGNORS `TO WESTERN ELECTRIC COMPANY, INCORPO- RATED, OF NEW YORK, N. Y., A CORPORATION 0F NEW YORK.

ELECTROMECHANICAL SWITCHING- SYSTEM.

Application led' May 25,

reference being had to the accompanying drawings, forming' a part of this specification.

Our invention relates to automatic switching apparatus and circuits, and while it may be applied to various purposes, it is particularly useful in telephone exchanges, -either automatic or semi-automatic or so-called auto-manual or in trunking connections through otherwise fully manual exchange systems. 1

' In order to illustrate an application of our invention we have worked out and shown in connection with this disclosure the details of the system as applied to the purpose of switching the in-coming calls on the A operators board of a 'manual telephone exchange system to and through the B operators board of the exchange. It is to be understood, however, that the electro-mechanical switching system of our invention is not limited to this particular use.

The general practice in manual telephone exchange systems is for a subscriber to call the operator located at the switchboard with which his line is permanently connected. The A operator at this switchboard answers the call by inserting the plug of one of her cords into the answering jack of the line upon which the call has been initiated. She inquires of the calling sub-y scriber the number of the line wanted. In a majority of instances, in large cities at least, the line wanted is permanently connected with some other switchboard or exchange of the system. It is therefore necessary for the A operator to select an idle trunk lineI leading to the switchboard of the exchange with which the called subscribers Specication of Letters Patent.

Patented Apr. 4, 1922.

1914. Serial N0. 840,768.

line is permanently connected. Having selected such an idle trunk line, either upon her own initiative or upon the receipt of instructions over an order wire from the B operators board,the A operator inserts the calling plug of the cord pair into the out-going jack of the selected trunk line. The operator at the B board completes the connection by inserting t-he plug of the trunk cord into one of the multiple s ring jacks of the line to be called.k The cal ed subscribers bell is rung in the usual way. When he answers the ring of his bell the telephone connection is completed and continues in this condition until the conversation is completed, whereupon appropriate signals are displayed to the operators, who then take downl the connection.

The mechanical and electrical installation necessary to switch calls in this manner is complicated and expensive. It involves, among other things, an enormous number of soldered connections with the multiple spring jacks of the B operators board. The operation of such a system is also complicated and gives rise to mistakes in establishing the proper connections with the line initially called for by the calling subscriber.

Our invention may be applied for the purpose of eliminating the B operator and the work done by her in establishing connections as above outlined. Our invention substitutes automatic means under the control of the A operator for establishing connection with the called line, thereby eliminating the errors due to misunderstanding between the A and B operators, There are, of course, at each telephone exchange both the A and B operators, and the B operators and their boards will be eliminated in both of the exchanges referred to in the typical example as above outlined. e

From the mechanical standpoint one ot' the important features of our invention is the multiple system. of wiring or contacts. in which each line is provided with a large number of sets of contacts throughv any one of which .connection may be established with the called line. Inaccordance withour invention this multiple is in t-he form of substantially continuous and rectilinear conductors taking the form of metallic strips or rods such, for example, `as long narrow metallic strips bent into the form required for stiffness, for mounting or for convenient Contact with movable contact members, o1'

as piano wires tightly stretched between appropriate supports. In practice, these wires when wires are used, one, two or three or four for each line, as the conditions of the case may require, are stretched or mounted vertically or horizontally between appropriate frame pieces of insulating material, the multiple for any one line consisting simply of the one or two or three or four wires arrangedl in a group and extending from the floor or for some distance parallel to the floor and part or all of the way to the ceiling of or across the room in which the switching mechanism is located. All of the lines are. provided with similar groups or sets of multiple wires or strips, the sets of multiple strips being conveniently arranged in numerical order and connected to other multiple strips by cabling or other means of cross-connecting when the number of switch contact sets used require more than one set or length of multiple strips.

vAssociated with this multiple system of stationary switch contacts is a set of moving switch contacts which, for convenience, we shall refer to as a plug, The plug is mounted upon a ncarriage adapted to travel longitudinally along the face of the multiple so as to carry the plug to a position in line with the set of multiple strips with which .connection is to be established. The carriage is provided also with means for moving the plug laterally so t-hat after it has been brought to tlhe proper longitudinal position it may be moved laterally between the several sets of multiple conta-ct strips until it has reached the lateral position occupied by the multiple strips of the line with which connection is to be. established. `When both the longitudinal and the lateral motions have been completed the plug is given a. thirdl motion, as for example a rotary movement, which rotary movement is adapted to throw out the moving plug contacts to bring them into engagement and electrical connection with.l the contact strips constituting the multiple of the line with which connection is to be established.

The line over which the ingconiing call has been received will, of course. be connected through the carriage with the switch contacts of the plug so that. the two lines will be interconnected upon the establishment of connections as above outlined.

further feature of our invention relates to the step-haast@ motion of the pl'ug contacts which are brought to such position that they may be rotated into electrical connec.

tion with the appropriate. set of multiple strips. 1n accordance with our invention the longitudinal motion of the carriage is divided into major steps and minor steps, corresponding with the major and minor orders of the numbers employed in designating the several telephone lines, and consequently designating the sets of contacts of the multiple system. The telephone lines are in conformity with the usual practice numbered in accordance with the decimal system. The multiple contacts are arranged in Iconformity with this system of notation. the banks of multiple sets being, for example, one hundred lines wide and one. hundred lines long, thus taking care of the connections to vten thousand different telephone lines'.

Instead of giving the carriage. a longitudinal movement divided into one hundred steps, it is the practice. in accordance with our invention,'to give. the carriage anywhere from zero to nine maj-or steps of movement in a longitudinal direction, each such major step having a length sufiicient to move the plug over the space occupied by ten lilies in the multiple system. The longitudinal movement of the carriage is divided also into minor steps, each such minor step corresponding with the longitudinal space occupiedby one line. The plug may thus be broughtopposite any one of the one: hundred longitudinal positions by a movement comprising from zero to nine major 'steps and anywherel from zero to nine minor steps. -lVhile it is our preference to give'the plug the requisite number of minor steps of movement before giving it the requisite number of major steps, it is entirely possible to reverse the order and give the carriage and the plug carried by iti the .requisite number of majori steps before giving it the requisite number of minor steps to bring it opposite any one. of the one hundred positions which must be aumed before the plug can be moved laterally into the position to make connection with the desired line.

The lateral movement of the plug is effected also by means of a combination of major and minor movements. The plug may be given the requisite number'of major steps followed by the requisite number of minor steps, or, as we prefer, the plug may be given the requisite number of minor steps followed by the number of major steps necessary to bring'the plug to the lateral posi-tion opposite the .set of multiple contact strips with which engagement is to be made.

As a refinement of the above idea of carrying the plug to any one of ten thousand. different positions in a given horizontal plane. it is our preference in practice to lequip the carriage with four substantially plugs is adapted to co-operate. Thus the multiple ma i be divided longitudinally into halves or su stantially into halves, whereby the plug or plugs at one end of the carriage will be employed in establishing connections with lines terminating in one end of the multiple, while the other plug will be employed in establishing connections with lines having contacts located in the other end of the multiple. In the same way the multiple may be divided laterally so that the multiple, instead of being located wholly upon one side of the carriage, islocated half, or substantially half, on one side of the carriage and half, or substantially half, on the other side of the carriage. ln accordance with this arrangement theplugs are adapted to be moved laterally in either direction from thev carriage as may benecessary to establishconnection with any line.A depending upon the location of the multiple of thatline upon one side -or the other of the carriage. This division of themultiple both longitudinally .and laterally into halves, or substantially into halves, together with an arrangement whereby the carriage and the plugs may be made to advance in either of two directions, materially reduces the total amount of movement which must be given to the plug contacts in order to bring them to a position in which they may establish connection with the desired line.

The carriages are preferably of a small vertical dimension so that a large numberof carriages may be used within the limits of one length of multiple contact strips or wires, by mounting the carriages one above the other or side by side. each independent of the other in so far as its movements and the movements of its plugs are concerned. Thus a large number of carriages may be employed in moving a correspondingly large number of plugs into the positions necessary to establish connections with any one of the many lines terminating in the multiple system.

It will be understood that the line initiating the in-coming call is connected either permanently or temporarily with the plug or plugs of one of the carriageswhereby the movement of the plug into position and then into electrical connection with the appro- 'priate set of multiple wires will serve to establish the desired connection between the in-coming line and the line to be called.

1t is not requisite to our invention that the responding movements both longitudinally and laterally. lt is only necessary in this extension of our invention to provide means for limiting the turning of the plugs to one or the other section of the carriage. as may be necessary to effect connection with a called line whose multiple set of contacts is located in'one or the other longitudinal section of the entire multiple system. The longitudinal step-by-step movement ofthe carriage and the lateral step-by-step movement of the ,plugs is controlled by automatic commutating mechanism which may be controlled by electrical impulses under manual control, or by variations in electromotive forces or resistances controlled by the operator or calling subscriber or otherwise, as will occur to those skilled in the art.

The advantages ot' our invention as above Outlined include the reduced expense of installation due to the simplicity of the mul,- tiple wiring and contacts, he decreased expense ,of operation because'ot t-he elimination of the operators employed in a. purely manual system for moving the connecting plugs to the proper position on the face of a multiple switchboard, 'the certainty with which connection is established with the desired line, the celerity with which the connection may be accomplished, the compactness of both multiple and switching mechanism for establishing connections as above outlined, the facility with which extensions of the system may be made, the very large number of lines which may be connected in a given multiple system, with any of which connectionl may be established,y the small number of serially-included contacts in the talking or switching circuits, and the simplicity and low cost of the automat-ic mechanism for vthus establishing connection with any one of an extremely large number of lines.` Furthermore, attention is called to the fact that the present automatic systems may be compared to the generally discarded and ineicient transfer systems used prior to the advent of the full multiple manually operated B board, while this switching system brings to automatic switching all the inherent advantages of a full multiple switchboard such as flexibility, simplicity of operation and circuits, and etc.

Theseand the other features of our invention and the detailsof the means by which it. has been worked out will more readily appear by reference to the accompanying drawings, in which- Figure l is a schematic pla-n or sectional view of the multiple system and the connecting mechanism arranged in accordance with our invention:

Figure 52 is a side elevation of a section of the multiple system together with a diagrammatic representation of a part of the carriage-actuating mechanism;

Figure 3 is an enlarged view in side elevation of a part of the multiple system;

Figure 4 is a similarly enlarged cross-sectional view of a section of the multiple taken on line 4-4 of Figure 3;

Figure 5 is an enlarged plan view of a portion of the carriage and its actuating mechanism, showing in detail the plug-actuating mechanism; c

Figure 6 is a cross-sectional vieu1 of the carriage and its associated mechanisms, taken on line 6 6 of Figure 5;

Fig. 6a is a detailed view showing the connection between the lead screw for moving the carriage and the carriage.

.Figure 7 is a partial cross-sectional view of the plug mechanism and the carriage, taken on line 7-7 of Figure 6;

Figure 8 is a partial cross-sectional view of the plug-and carriage mechanism; taken on line 8 8 of Figure 6;

Figure 9 is a partial cross-sectional view of the plug andcarriage mechanism, taken on line 9-9 of Figure 6;

Figiu'e 10 is a detailed 'view in end elevation of a part of the plug-actuating mech-v anism, parts being broken away to more clearly reveal the internal construction;

Figure 11 is a. detailed side elevation of the mechanism connecting two sections of the carriage, parts being broken away to more clearly reveal the internal construction;

Figure 12 is a detailed view of the plugturner mechanism; y

Figure 13 is a diagrammatic view representing the electrical circuits and electromagnetic apparatus employed in the operation of our invention;

Figures 14, 15, 16 and 17 are diagrammatic detail illustrations ofthe commutatore controlling the longitudinal movement of the carriage mechanism; l

Figure 18 isa diagrammatic view showing in detail the mmutation and relay mechanism for controlling the plug turners and the selection of the ten thousand multiple the commutators illustrated in Figures 14 and 17 inclusive, and the cooperating -mechanism.

Figure 26 is a front elevational view of the commutators illustrated in Figures 19 to 22 inclusive, and the mechanism cooperating therewith. f

In describing the detailed embodiment of our invention illustrated in the accompanying drawings We shall first describe the mul, tiple, then the carriage and the plugs carried We shall describe the circuits and mechanism for controlling the movements of the plugs.

In Figure 1 the cross-lined and serially numbered areas at either side 'of the longitudinal axis may be taken as diagrammatically illustrating in plan or'cross-section the banks of multiple contact strips. Figure 4 illustrates in horizontal cross-section a fragment of a multiple bank, While Figure 3 illustrates a front elevation of the same fragment. It will be noted that this fragment is broken on line 304-30 in Figure 4 because of lack of space to illustrate theeentire fragment. The parts of an entire bank ,which are thus shown substantially full-sizcd in Figure 4 are indicated by the diagonally cross-hatched patches at the upper left-hand corner of Figure 1. `Separated by a vertical distance of, say, six or eight inches are a series of steel angle irons 31, 31. These may be regarded as located at the side of the multiple bank adjacent to the carriage. The construction can conveniently be described in connection with the assembly ofthe parts,

The clamping bolts 32, 32 will be inserted from the carriage side of the angle irons 31 to assume the positions shown in Figure 4, the nuts 33,33 being omitted for the time being. i The bolts having been placed in position, a hard rubber spacing strip 34, which is drilled with appropriately spaced holes for the reception. of the bolts, is slipped over the clamping bolt from the back or side opposite that occupied by the carriage. One such spacing strip will be slipped into place at the back of each of the several angle irons 31, which, as best indicated in Figure'2, may

be of any number, one above the other, such as may be necessary to give proper support to the multiple Ycontact strips. When the first series of spacing strips one -above the other has been brought into position immediately behind the several angle iron supports, one of the `four Contact strips or wires of each multiple setis' laid in position in a semi-cylindrical notch cut in the rear face of each strip at each of the positions assigned to a line. We have indicated four contact strips or Wires assigned to each line, the four strips assigned to each line being designated by the 'characters a, b, c and d, respectively. We have thus endeavored to thereby and the motion thereof, after which point out that after the first vertical series of spacing strips is in place, all ot the multiple contact strips designated by the char- 'dicated at 35 in Figure 4 have been laid in position, the second series of spacing strips 36 is slipped over the clamping bolts from the rear and brought into engagement with the wires a, b; a, b; a, o lying in the plane 35. The spacing strips 36 ot this second series are provided with lsemi-cylindrical notches to receive and clamp the wires a, (L and I), b on the side toward the carriage and are provided with appropriate notches on the rearward side also to receive the wires (l, d, and c. c lying in the plane indicated at `37 in Figure 4l. After the second series of spacing strips has been placed in position as indicated in Figure al, the wires (I, c; c; (I c lying in the plane indicated at 37 are laid in position. Thereupon the next series of spacing strips l38 is slipped over the bolts. This is followed by the series of multiple contact wires lying in the plane 39; The entire bank is laid up in this way. First a series of hard rubber spacing strips and then a series ot multiple contact strips or wires. lllhen the entire bank has thus been laid up from front to back, the hard rubber backing plates 40, 4() in the shape of thin hard rubber sheets are pushed in between the vertically separated. groups of spacing strips 34, 36, 33, etc., the backing plates being supported vertically by the spacing strips upon which they rest and being supported laterally also by the multiple contact wires between which they are slipped from the' rear and being held in position also at the front by the rearward faces of the angle irons against which they abut. After the backing plates have been slipped into position as above described, the metallic clamping plate 41 is slipped over the bolts, whereupon the nuts33, 33 may be screwed onto the bolts ends and tightened to clamp the component parts ot' the multiple bank in place upon the angle iron supports 31, 3l. The backing' plates serve principally to support the multiple contact wires against the pressure ot the plugs, as subsequently to be described, thereby effectively and certainly insulating the several wires from one another. For simplicity, we have not attempted to show the framework which will support the construction as above routlined in place. This can be supplied by those skilled in the art to meet the particular requirements ot each installation, The multiple bank as above described can be completely assembled in the factory before shipment to the exchange in which it is to be installed. lllhilel the foregoing description ot the multiple arrangement and the following outline of the apparatus and circuits have` for the sake of brevity, been limited to an arrangement consisting ot' four wire groups, it is conceivable and eminently practicable to arrange the multiple into one wire, two wire, three wire or other combinations as needed to tit conditions, by simply changing the arrangement of the multiple, apparatus and circuits.

`We have not made particular point ot' the fact that the multiple contact strips, (l, (Z are flat or ribbon-shaped in cross-section, whereas the other wires of the multiple may be round. Our purpose in illustrating one of these wires as ot flat or ribbon shape cross-section is to indicate that one ot' the wires may be located so that its contact face will project farther into the space between the wires of each multiple set. This location of one wire of each set in the multiple may be availed of il desired to control by appropriate electromagnetic apparatus the movement of a plug. as tor example, in selecting or picking an idle trunk line` Tn case this construction is employed, the plug will be moved between the multiple wires of the several sets until one contact on the plug wipes across the inwardly projecting -tace o a multiple wire (Z whose electrical condition is in one way or another different from that ot the other multiple wires d across which it has passed, and when it thus reaches the multiple wire having the difterent electrical or mechanical condition referred to, apparatus will be controlled to etl'ect the turning ot a plug or in some other way the engagement of its other contacts with the multiple wires ot the set which has thus been automatically selected. "This construction may, therefore, be employed to stop automatically either by electrical or mechanical means the traveling of a plug in order to secure the advantages to be obtained in the use of certain automatic and semiautomatic exchange systems of the prior art.

Figure 2 is an illustration upon a smaller scale ot that side of the multiple bank away from the carriage. tio far as the multiple is concerned it illustrates principally the fact that the multiple can be extended indefinitely in a vertical direction. No attempt has been made to illustrate all ot the details of the multiple in this Figure 2. lts purpose is principally to indicate the vertical disposition or" the plugcarriages one above the other, several of the plug carriages and their actuating mechanisms being located between each vertically separated pair of angle irons, spacing strips, etc. ln Figure 2 we have indicated the multiple contact strips as continuing beyond the lowermost and the upper lll most sets of spacers. It will be understood that thesevwires may be provided at thelr upper and lowermost ends with means for maintaining them taut and' straight 1f they do not have the inherent rigidity necessary to maintain them in proper position as il? istrated in Figure 4. For the sake ot' simplicity the foregoing description shows a vertical arrangement only of the multiple and associated plug carriages. It is evident that an equally good or even better arrangement may be obtained by mounting the multiple wires horizontally and the plug carrlages side by side, thus permitting the use of many more associated plug carriages in relation to a particular sectional length of multiple than would be possible in a vertical arrangement which may bc more limited by the height of the ceiling. Furthermore, in order to shorten the description, only one method of mounting the multiple contact strips is shown; it is evident that fiat or other shaped strips may be used, and that the strips may be mounted differently by fastening them to an insulating backing and mounting the backings in a frame, or as may be most practicable in practice.

It is to be understood also that each telephone line will be more or less permanently connected through the usual distributing frames with a particular set of these multiple wires. In Figure 4 we have indicated in the spaces between each group or set of multiple wires the call number4 of the telephone line to which the group or set is assigned and connected through the distributing frame. The assignment of the numbers to the several sets of multiple wires follows a definite prearranged plan, in accordance with which the numbers have been filled in upon the fragment of the multiple bank illustrated in Figure 4. These numbers as thus arranged in detail, takerl in conjunction with the numbering appearing upon the margins of the banks as shown in Figure 1, will suficiently indicate the scheme of designation and distribution.

In describing the assignment of the telephone numbers to the several sets of multiple wires or contact strips wc shall refer to the direction in which li'es the carriage lead screw 42 as the longitudinal direction and the direction at right angles to this lead screw as being lateral. It may clarify the description of the assignment and distribution' of the numbers to anticipate our description slightly by saying at this point that in Figure 1 tour multiply connected plugs are indicated at 43, 44, 45 and 46. The connecting carriage which as a whole is indicated at 47 in Figure 1 is given a longitudinal motion suiieient to move a plug longitudinally until it occupies a position opposite the space between the set of four multiple wires with which connection is to be established. The plug which is to establish the connection is then moved laterally away from the carriage and between the several sets of multiple wires or contacts until it reaches a lateral position opposite the particular set of multiple Contact wires with which the connection is to be established. The plug is then rotated or given a motion of a third character such that the contacts of the plug will establish electrical connections with the set of multiple wires connected with the line with which connection is to be established. We shall not stop at this point to describe in detail the mechanismv for effecting these movements of the plugs, this being a matter which will be fully explained during the subsequent description of this embodiment of our invention.

It will be apparentnow or a little later thatthe general plan of our invention might be employed in a system having but a single plug for each carriage, in which case the single plug must be capable ot a longitudinal motion from one end of the entire multiple bpnk to the other end of the entirebank` and in which case also the plug must be capable of a lateral motion sufiicientl to reach the multiple wires of any line no matter how tar removed from the carriage. This arrangement is applicable for a small ofiice or for use when the selectors are arranged tor connection to interotlice trunks in a full automatic system. but for the sake ot' compactness, however, and tor the sake also ot' minimizing the amount of travel necessary to give the plugs, both longitudinally and laterally. it is our preference especially when there is a large number of lines to provide each carriage With at least four plugs, one only of which, however. becomes effective in establishing the desired connection. These plugs rest normally in thc positions shown in Figure 1. The carriage and therefore the plugs are first given anywhere trom zero to nine minor' steps ot' longitudinal motion. the number of these minor steps corresponding with the digit in the units order ot' the number of the telephone line to be called. Let us assume, for example, that the number' of the line to be called is 9867. Since the digit in the units order is a seven. the carriage is first given seven minor steps oi movement in a longitudinal direction and toward the lett as shown in Figure 1. Each minor step ot longitudinal movement corresponds in length with the distance between sets ot' multiple wires, as illustrated in detail in Figure 4 and as indicated by the finest vertical lines representing the multiple banks in Fig- 1 ure 1. I tfwill be noted that the row of sets of multiple wires opposite which plug 43 stands normally is numbered at the upper margin of Figure l as (l". Seven minor steps of motion will therefore carry plug 43 to a position opposite a row.of multiple contacts numbered at the upper margin with a small numeral 7. The digit` representing the tens order in the assumed number 9867 is a 6. The carriage is` therefore, to be given a number of major lsteps of movement in the left-hand direction. The major steps of longitudinal movement are toward the left rather than toward the right because the digit in the units order of the number to be called is a 5, or ay 6, or a T. or an 8. or a 9 rather than a (l, or a l. or a 2. or a 3. or a Lt. lf the digit in the units order were a 0, or a l. or a 2. or a 3. or a 4, the major steps of longitudinal motion would be to the right instead ofthe left. Reverting now to the order of procedure in the case of the number 9867, the iarriage, and therefore the plug 43. is given three major steps of movement toward the left. The major steps of longitudinal movement have a length equal to five of the minor steps-in other words. a length equal to the length of five sets of multiple wires. The first major step of movement toward the left will. therefore, carry the plug 43 from a position opposite the small numeral T atthe upper margin of the multiple bank in Figure l to a position opposite the next small numeral T to the vleft and, as it happens, directly under the. larger numeral 2 atthe upper margin of the figure. The second major step of movement will bring the plug 43 to a position opposite the row of multiple sets marked with the next succeeding small' numeral T. this time directly under the larger numeral 4. The third major step of movement towardl the left will bring the plug 43 opposite that row of multiple wires designated with the small numeral T next to `the left andk in this instance directly under the larger numeral 6. The larger numeral (i at the upper margin of the figure and over which is placed a brace (Phs) is intende-d to designate the five lateral rows of multiple contacts within the brace as connected with lines designated with numbers having the digit 6 in the tens order. Thefive lateral rows of multiple contacts within this brace are. first. the lines having numbers with' the digit 5 in the unit-s order: second, the lines having numbers with the digit 6 in the units order: third, the lines having numbers with the digit 7 in the units order.; fourth. the. lines having numbers with the digit 8 in the units order: and fifth. the lines having numbers with the digit 9 in the units order.

lt. may be well now to point out that there is another group of multiplewires or sets.

assigned to. lines whose numbers have the digit 6 in the tens order. 'lhese are the lines. however. whose numbers have the digits (l. 1, 2, 3, or 4 in the units order. This additional group of multiple sets assigned to lines whose numbers have the digit 6 in the tens order are designated by the larger numeral 6 at the upper margin of Figure l and around which we have placed a bracket (H).

lf, therefore, the number called had been 9863 instead of 9867, the first motion would have been three minor longitudinal steps to the left, followed by three major longitudinal steps to the right. This would have brought plug 43 opposite the multiple section enclosed within the bracket and bearing the larger numeral 6 and opposite the parrticular row within this section which is designated with the small numeral 3.

To further decrease in the same general way the distance which it is necessary to move the carriage in a longitudinal direction, we divide the multiple contacts of the bank into two major groups, longitudinally divided, and connect all of the lines having numbers with an even digit in the tens order with multiple contact sets in the left-hand group, and all of the lines having odd num bers in the tens order with multiple contacts in the right-hand major group. Corresponding with this sub-division of the. multiple bank we lprovide the carriage with two plugs or lines of plugs longitudinally separated, it being the purpose of the plugs at the left-hand end ofthe carriage to cooperate with and establish connections with multiple vwires in the left-hand half of the multiple bank, and it being the purpose of the plugs'at the right-hand end of the carriage to establish 'the connections with the lines terminating in the right-hand major group `of the entire bank.

Having adapted this arrangement. it will be apparent that the two plugs or lines of plugs will be given the same longitudinal motion or motions. since the two\plugs or lines of plugs are mounted upon the same carriage through which all of the longitudinal movements are imparted to the plug mechanism. lf we were to provide certain more or less complicated mea-'ns for de termining which of the two plugs or lines of plugs is to be turned to establish connection with a line` it would be entirely feasible to arrange the multiple sets in both of the major groups of the bank in exactly'the same way. rl`his would resiilt in bringing the plug atthe left-hand end of the carriage opposite a certain number having an even digit in the tens order. at the Asame time. bringing the plug at the right-hand end of the carriage opposite a multiple set having the same number except in the tens order, where the number would have an odd digit in the tens order instead of an even digit. llt', now, we were to provide means for selecting or'determining which of thetwo plugs was to be turned or otherwise brought into electrical connection with a multiple set, it would be entirely feasible to arrange the two groups of the multiple bank precisely as we have already described in connection with the left-hand group.

By slightly altering the arrangement of the right-hand group of the multiple it is, however, possible to simplify greatly and to make entirely automatic in its operation the means for determining which of the two plugs or lines of plugs is to be made effective in establishing the final connection with the called line.

Referring to Figure 1 it will be noticed that the right-hand group of multiple sets and its relation to the plug or line of plugs at the right-hand of the carriage differs from the arrangement at the left-hand end in two particulars: First, in that the plug 45 normally stands opposite a row of multiple sets designated by the digit l (instead of O) in the units order; and second, in that there is, through the center of the group, a vacant space equal in width to the distance between two rows of multiple sets of contacts.

In conformity with these differences in the arrangemen of the multiple in the right-hand group and the arrangement of the multiple in the left-hand group, the first step of the movements employed in making a set-up in conformity with the digit in the tens order has a length equal to that one of the minor movements heretofore described instead of the length of a full major movement.

It will be apparent that if the digit in the tens order is a O, it will not be necessary to impart any movement to the plug 43 in conformity with the set-up of the digit in the tens order. This is for the reason that the plug 43 normally stands opposite the rows of multiple wires connected wit-h lines whose numbers are zeros in the tens order. When, therefore, the plug 43 has been given a number of minor movements corresponding with the digit in the units order, it is already opposite the proper row of mult-iple wires or contacts, all of whose multiple wires are connected with lines whose numbers have zeros in the tens order.

One would expect ordinarily that in the case of the multiple wires connected with lines whose numbers have the digit 1 in the tens order, .it would be equally unnecessary1 to impart any additional motion to the plug 45 in effecting a set-up corresponding with a called number having the digit 1 in the tens order. One would naturally expect this to be the case because of the fact that the plug 45 normally stands opposite the group of multiple contacts assigned to lines' having numbers containing the digit 1 in the tens order. n I

But for the sake of simplicity 1n the commutating and actuating mechanism, it is desirable to -give both sets of plugs, that is the set 43 and 44 and the set 45 and 46, the same lateral motions and by means of the same mechanism. It is necessary, therefore, to determine which of the two plugs or sets of plugs is to be turned to establish the final electrical connection with a multiple set, and in order to secure the commutation necessary to determine which plug or set of plugs is to be turned it is convenient to give to the carriage one extra ste-p of longitudinal motion whenever the called number has an odd digit in the tens order. This extra step of longitudinal motion must, therefore, be given to the carriage and the plugs whenever the digit inthe tens order of the called number is a 1, as well as whenever the digit in the tens order of the called member is any other odd digit.

Vhile it would be entirely feasible to make this extra step. of longitudinal motion of a length equal to the major motions heretofore described, space and motion can be saved by making this extra step of movement of a length equal to the minor movements heretofore described, and the minor movement is suiiicient to effect the necessary commutation. It is our preference, therefore, to make this extra step of longitudinal motion of the length of the minor steps heretofore described, but the motion can most conveniently be regarded as the first step of the major or second series of longitudinal motions because it is employed in effecting the set-up corresponding with the digit in the tens order rather than the digit in the units order.

This will be more readily understood by illustration than by abstract description. Let us assume, for example, therefore, that the number to be called is 9817 instead of 9867 The carriage is first given seven steps of minor movement toward the left. This will carry plug 45 from its position opposite a row of multiple sets assigned to lines having the digit in the units order to a position opposite the row of multiple sets assigned to lines whose numbers have the digit 6 in the units order. The row of multiple sets opposite which the plug 45 will be left are assigned to lines whose numbers have the digit 6 1n the units order and the digit l in the tens order-in other words, opposite the row of multiple sets* assigned to lines Whose numbers end in 16.7 The number to be called, however, was 9817 and not 9816.

When the second series of longitudinal movements occurs the carriage is first given an extra movement of a length equal to the minor movements, in view of the fact that the digit in the tens order is an odd number rather than an even number. The carriage and the plug 45 are, therefore, given one step of movement toward the left as determined by the fact that the digit in the tens order is a 1 rather than a 3, or a 5, or a 7, or a 9, and since this movement 1s of a length equal to the minor movements heretofore described, t-he plug 45 will be moved from a position opposite the row of the multiple sets assigned to lines having numbers Wlth the digit G in the units order to a position opposite the row of multiple sets assigned to lines having the digit 7 in the units order. In other words, the plug 45 Will thus be brought opposite the row of multiple sets assigned to lines Whose numbers terminate in 17. This conforms with the number to be called, namely, 9817.

If the number called had been 9813 instead of 9817,A the carriage, and therefore the plug 45, would first be given three minor steps of movement toward the left. This would bring plug 45 opposite the row of multiple sets assigned yto lines whose numbers have the digit 4 in the units order and the roW opposite which the plug is thus brought would be within the group assigned to lines having the digit 1 in the tens order. This, however, is not the row of multiple sets within which connection is to be established. lVhen, however, that part of the set-up corresponding with the fact that the called number has the digit 1 in the tens order is effected, the carriage, and therefore the plug 45, will begiven an extra step of movement having a length equal to the minor movements heretofore described. This time, however, the carriage and the plug 45 Will be moved one step to the right instead of one step to the left. This is determined by the fact-that in the units order of the called number there is a 0, or a 1, or a 2, or a 3, or a 4 rather than a 5, or a 6, or a 7, or an 8 or a 9. The first of the second series of longitudinal movements having the length of a minor movement will, therefore, move the plug 45 from a position opposite the rovv of multiple sets assigned to lines Whose numbers terminate in 14 to a position opposite the row of multiple sets assigned to lines Whose numbers terminate in 13. In the case of the number 9813, selected as an example, the second series of movements will consist of this single movement only, because no former movement is required to bring the plug 45 opposite the proper row of multiple sets.

Let us illustrate further by assuming an example in which the second series of movements involves or requires more than one step. het us assume, for example, that the number called is 9857 instead of 9817, as previously selected. The seven steps ofminor movement conforming with the digit 7 in the units order will first take place, thus bringing the plug 45 opposite the row of multiple sets assigned to lines terminating in MV1 as igireviousiy described. Following this and conforming with the part of the setup which takes care of the digit in the tens order, the carriage and the plug 45 Will be given first the extra one' step of movementof a length equal to the minor steps heretofore described. This Will carrysthe plug 45 from a position opposite the row of multiple sets assigned to lines terminating in 16 to a position opposite the row of multiple sets assigned to linesterminating in 17. The next step of the second series of longitudinal steps is of the major length as heretofore described, and as the movement will be in the left-hand direction as determined by the magnitude of the digit in the units order, the plug 45 will be moved from a position opposite the row of multiple sets assigned to lines Whose numbers terminate in 17 to a position opposite the row of multiple Sets assigned to lines Whose numbers terminate 1n 37. The third of the second series of longitudinal movements is also of a major lengthand will carry the` plug 45 from the position opposite the row of multiple sets assigned to lines Whose numbers terminate in 37 to a position opposite the row of multiple sets assigned to lines Whose numbers terminate in 57. This example. is typical `and illustrates the fact thatwhenever the called number has an odd digit in the tens order, the first of the second series of longitudinal movements Will be of a length corresponding with the minor movements which take care of the set-,up representative of the digit in the units order, after which the remaining steps of the second series of movements will all be of the major length, the number of major steps being determined, of course, by the particular odd digit in the tens order of the number to be called. As previously described, the movements will be t0 the left or to the right, as the case may be, depending upon Whether the digit in the units order of the number' called falls between O and 4, inclusive, or between 5 and 9, inclusive.` i

In the example last selected, and described it will be seen that the plug 45 has been brought opposite the row of multiple sets assigned to lines whose numbers terminate in 57. To further illustrate a. typical ex ample, let us assume noiv that the number called had been 9853. ln this case the plug 45 would first be moved three minor steps toward the left, thus bringing the plug 45 opposite the row of multiple sets assigned to lines having numbersA terminating in 14. The fact that the number to be called has a 5 in the tens order will determine that the second `series. of longitudinal movements is to be of three steps, and the fact that the digit in the units order of the called number is less than five will determine that the. second series of movements is to be toward the right rather than the left. 1n effecting the setup corresponding with the digit in the tens order, the carriage and the plug 45w1ll first be moved one step toward the right, this ste being equal to the minor steps in. length an moving the plug 45 from a position opposite the row of multiple sets assigned to lines whose numbers terminate in 14 to a position opposite the row of multiplesets assigned to lines whose numbers terminate 1n 13. The second of the second series ot longitudinal movements is of a major movement in length and will carry the p-lug 45 from its position opposite the row assigned to lines Whose numbers terminate in The next step of longitudinal movement is also of a major step in length and will carry the plug 45 from the position opposite the row assigned to lines whose numbers terminate 1n 33 to a position opposite the row assigned to lines whose numbers terminate in 53. This second series of longitudinal movements, three steps in number-first, the extra step of minor length and then the regular steps of major length--will carry the plug 45 to a position opposite the row of multiple sets at some point within which the line having the called number 9853 is connected.

It may be well to call attention again at this point to the fact that both lines of plugs,that is, the line represented by plugs 43 and 44, as well as the .line represented by plugs 45 and 4G-are brought opposite a row of multiple wires or contact sets. The plugs 43 and 44 will be brought to rest opposite a row of multiple sets assigned to lines whose numbers have even di 'its in the tens order, while the plugs 45 an 4G will be brought to rest opposite a row of multiple sets assigned to lines whose numbers have an odd digit in the tens order. Both lines of plugs are now moved laterally by equal amounts, but the connnutation which is effected in connection with the extra step of movement of a. minor length falling within the second series of longitudinal movements as above described 1s made available in determining automatically Whether it is the line of plugs represented by 43 and 44 or that represented by the plugs 45 and 46 which is turned at the conclusion of the set-up to establish connection with the called line. The commutation is effected in such a manner as to effect the turning ot' one line ot' plugs, and it will be apparent from the. general description and the examples cited that it. must be the line of plugs represented by 43 and 44 which is to be turned in case the called number has an even digit in the tens order, whereas it will be the line of plugs represented by 45 and 46 which must be turned in case the alled number has an odd digit in the tens order.

We come now to a consideration of the lateral motions or movements which must be given to the plugs in order to bring them to the lateral positions opposite the longitudinal rows of multiple sets assigned to lines whose numbers have the digits in the hundreds and thousands orders conforming with the digits in the hundreds and thousands orders of the called numbers.

It will be noted that the multiple bank is divided laterally into two groups, the group containing the multiple sets assigned to lines whose numbers contain the digits 5, 6, T, H or 9 Ain the hundreds order lying on one side of the carriage, and the multiple sets assigned to lines whose numbers contain the digits (Y), 1, 2, 3 or 4 in the hundreds order lying on the other side of the carriage. This division into the two lateral groups is not `followed in the case of the multiple sets assigned to lines of the zero thousand and containing the digits 0, l, 2, 3 or 4 in the hundreds order, these multiple sets being grouped with the multiple sets assigned to lines whose numbers contain `the digits 5, (3. 7 or 8 in the hundreds order. ril`here are, therefore, more multiple sets in the lateral group at the upper side of the carriage than at the lower side, as illustrated in Figure 1.

After the plugs have been given the necessary longitudinal movementg as heretofore described, they are given the necessary lateral movements. These lateral movements are accomplished step by step, as in the case of the longitudinal movements. The lateral movements are divided into two series: first` a series of minor movements from one to ten innumber, and then a series otl major movements frOm zero to nine in number, the minor movements always 'taking place in one direction and the major movements Ataking place in either of two directions.

Thesemovements may conveniently be described in -tonnection with particular examples. llet us assume, therefore, that line 9867 is to be called, and let us assume also that plug 43 has been moved longitudinally until it stands opposite the row o't' multiple sets assigned to lines 'whose numbers terminate in (il'. rlhe digit in the hundreds order will in this case be an 8. The two lines of plugs-namely, the line represented by 43 and 44, and the line represented b v 45 and Liti-will be given nine steps ot' minor movement toward the top of Figure l. The first step of minor movement will carry the plugs within the upper group, as illustrated in Figure l, ,and opposite the lateral row ol' multiple sets assigned to lines having num bers the first two ot' whose digits are (l, l). The second minor step will carry the plugs into the lateral row representing numbers beginning with ()L7 rll`he third step ol' lateral movement will carry the plugs opposite the lateral row assigned to lines whose numbers begin with 02" This step-by-step movement will be continued until at the end of the ninth minor step the plugs will lie within the lateral row of multiple sets asAV signed to lines whose numbers begin with 08. This ends the first series of lateral movements.

In the case of the selected number, 9867, there will then follow the second series of lateral movements, ea'ch step of this second series of movements having the length of a major movement, i. e., a distance equal to five minor steps of movement. The first major step, which in this instance takes place from the carriage toward the top of Figure 1, will carry the plugs from the lateral row representing numbers beginning'with 08 to the lateral row representing numbers beginning with 18. The next major step ot movement will carry the plugs into the row representing numbers beginning with 28. Successive major steps will vcarry the plugs into the rows representing numbers beginning vvitll 38,57 648,77 58,37 68,77 6678,77 48857 and 98, nine such major steps being required to carry the plugs into the 800 row assigned to 9000. The plug 43 will at the end of these two series of lateral movements lie within the area defined by the four multiple wiresl in that direction only when the digit in the thousands order of the called number is more than zero and when the digit in the hundreds order is a 5, or a 6, or .a 7, or an 8, or a' 9. lf we had assumed that line 9367 was to be called, the minor steps of lateral movement would take place as before, except that the minor steps would in this case be four in number instead of nine in number as previously described. The four steps of minor movement would carry the plugs 43 and 45 into the lateral row representing lines having numbers beginning with 03 A tter this nine steps of' major movement will ensue` and since the digit in the hundreds order of the number to be called is less than five, the movement will take place toward the bottom of Figure 1 instead of toward the top, as previously described inl connection with the number 9367. The first major step of movement will carry the plugs 43 and 45 outside the lateral group at the top of Figure l, but will carry plugs 44 and 46 into the lateral group at the. bottom of Figure 1 and into the lateral row assigned to lines having numbers beginning with 13. The second major step will carry plugs 44 and 40 into the lateral row representing lines having numbers beginning with 23. The successive major steps will carry the plugs 44 and 46 successively into the lateral row representing lines having numbers beginning Vith t 33,77 L 43,75 t 53;? C 63,37 C 73:5 (L 3f and 93, it being apparent that nine major steps of movement will have carried the plugs 44 and 46 into the lateral row representing the lines having numbers in the thousands and hundreds orders in which the number of the called line is located. namely. 9367.

Here again the turning ot' plugs 44 upon its axis will effect the connection with the called line. lVhile the lateral movements necessary to bring plug 44 into the position corresponding with line 9367 have taken place, the plug 46 will have been carried into the position occupied by the multiple set assigned to line number 9376. The commutation controlled by the second series ot longitudinal movements will determine, however, that it is plug 44 which is to be turned rather than plug 46. Plug 46 will not. therefore, be rotatedupon its axis to establish connection with line 9376.

lf the number called had been 0367, the first series of lateral movements would have comprised four minor steps toward the top ot' Figure l, as previously described. This first series of' lateral movements wouldl have brought plugs 43 and 44 into the lateral row assigned to lines having numbers beginning with 03. No further movement of the plug is necessary, therefore, and the second series of lateral movements may in this instance be regarded as zero in number. ln the case of' called numbers having the digit 0 in theA thousands order, it is, however, necessary to give the plugs one step of' minor movement, as a result of which the first series of lateral movements may be regarded as comprising a single minor step.

It will be apparent now that'the multiple bank contains a set of multiple contacts assigned to each of the lines numbered from 0000 to 9999, and that at each vertical level an inch or two apart'may be located a plug carriage and plugs which, by a series otl longitudinal movements followed by a series of lateral movements, may be brought into an area lying between multiple wires assigned to any line. The proper plug having been brought to the proper position within the multiple bank, it is only necessary to turn the plug upon its axis in order to establish connection with the called line.

Thus far we have described the multiple bank and the carriage and plug mechanism as though limited in capacity to 10,000 lines. An exchange equipped with our invention is not, however, thus limited to a capacity of 10,000 lines. ln order to secure a capacity ot' 20.000, it is only necessar)v to duplicate the multiple banks which are shown in full in Figure 1, these multiple banks being arranged immediately to the right ot the banks shown in Figure l. A fragment of the second multiple bank of 10,000 is illustrated at the extreme right of Figure 1. The number of the lines assigned to multiple sets in this duplicate bank will be from 10,000 to 19,999, the digit 1 in the ten thousands order being the symbol which will distinguish lines terminating in the duplicate bank from those terminating in the first bank already described. Between the two lateral groups constituting the duplicate bank is a carriage equipped with plugs identical with those designated by the reference letters 43, 44, 45, 46 and 4T, this duplicate carriage being mechanically connected with the carriage shown in Figure 1 by means of the angle irons 48 and 49. The duplicate carriage will, therefore, move longitudinally in exact conformity with the carriage 4T, shown in Figure 1.

The mechanism not yet described for moving the plugs of carriage 47 in either of the two lateral directions is carried through the duplicate carriage so that the plugs of the duplicate carriage will be Inoved laterally in exact conformity with the plugs of the carriage 47.

Each of the carriages is provided with its own individual plug-turning mechanism and commutation is provided to determine automatically whether it shall be a plug in the duplicate carriage or in the main carriage 47 which shall be turned at the end of the series of longitudinal and lateral movements heretofore described. Since means is thus provided for determining whether it shall be a plug in the main carriage or a plug in the duplicate carriage which is to be turned, we provide a means for establishing connection with any one of 20,000 lines. The number of multiple banks and carriages is not limited to two. lVe may provide av triplicate multiple bank assigned to lines having numbers from 20,000 to 29,999 and equipped with a. triplicate carriage mechanically connected with the two carriages heretofore described. The triplicate carriage will be provided with its own independent plug-turners controlled by appropriate commutation such that a plug in any one of the three carriages will alone beitu'rned to effect connection with the called line and no other.

rIhe system and its principles are not limited to three multiple banks adapted to accommodate 30,000 lines, but as a matter of theory or principle. at .least may be ei;- tended indefinitely. ille do not fail to appreciate, however, that there may be practical limits which it would be unwise to exceed.

llilhile it is conceivable that the carriages and plugs mightl be cactuated manually move longitudinally and laterally as hereinbefore described, it is our purpose to provide automatic mechanism for controlling and actuating the carriages and plugs. This nism might utilize mechanical, pneumatic or other power, but it is our preference to employ electromagnetic means for controlling and effecting the actuation of the carriage and plug mechanism.

The controlling and actuating mechanism can best be described by following the diagrammatic circuit drawing of Figure 13 with such incidental reference now and then to the details of the mechanical illustrations as may be necessary or helpful'in following the circuits and the functions thereof.

Before proceeding to a detailed description it may be well to outline the circuit. arrangement and the controlling and actuating mechanism. The longitudinal movements of the carriage are effected by means of the lead screw 42. An electro-mechanically controlled clutch is arranged to throw the lead screw into mechanical connection with an elect-ric motor, the motor thus serving to drive the lead screw and to move the carriage forward or backward as may be necessary. p

The plugs are mounted upon the ends of racks guidedto permit of their transverse movement across the carriage in either direction. rfhe racks upon the ends of which the plugs are mounted are in mesh with pinions splined upon driving shafts running from end-to end of the space over which the carringe is adapted to travel, with the result that the rotation ofthe splined shafts will effect the lateral or transverse movement of the racks upon the ends of which t-lie plugs are mounted. The splined shafts are adapted to be connected through suitable clutch mechanism at the forward end with the electric motor previousl)v referred to.

Associated with each carriage is also a plug-turning rod, the rotation of which is adapted to effect the rotation of a plug` no matter where the plug may be loc-ated, longitudinally and laterally relative to thc multiple bank. The. plug-turning iod or rods are actuated b v electromagnets.

The operation of the motor which supplies the power to the lead screw and the spindle shafts and the electromagnets controlling the clutches is under the control of electromagnetic relay and switching nicchanisni primarily cqntroll'cd b v a suitable sendingdevice adapted to be manipulated by the operator or telephone subscriber upon the calling line. 'lllhe manipulation of the second device determines the sequence and extent to which the automatic switching mechanism is operated in controlling the application of current to the devices which supply and control the application of power to the carriage and the plugs mounted therein.

rlilhe mechanism which is directly effective in actnatingthe carriage and the plugs is best illustrated in Figures 1', 5, 0, 7, t3, 9

llO 

